BPW vs ISO BPW, what’s the difference?

Buffered Peptone Water (BPW) is widely used in the enrichment of Salmonella in pathogen detection assays. Similarly, we use BPW with a proprietary supplement in our new product, Solus One Salmonella, as the single enrichment media. For optimum results we recommend the use of Solus BPW, which is ISO formulation pH7. But what if you already use BPW in your lab? What if it’s from a different supplier and not ISO formulation? Can you use a non-ISO formulation and will it still work in the Solus One Salmonella assay?

ISO and BAM vs Reference BPW

With these questions in mind, we conducted a study to compare ISO formulated BPW with the FDA equivalent. The FDA describes the BPW formulation, referred to as BAM Media M192, in the FDA Bacteriological Analytical Manual (BAM). We used both variations of BPW for single enrichment in the Solus One Salmonella assay and compared against the reference method ISO 6579-1. We carried out the evaluation with two food matrices (raw salmon and cheddar cheese) and a stainless-steel environmental surface. These were some of the same matrices and environmental surface as analysed at the Expert Laboratory during our AOAC PTM validation.

The conclusion of our study was that there is no significant difference between either media formulation when compared with the reference method. Therefore, yes you can confidently continue to use your usual formulation of BPW with the Solus One Salmonella assay.

You can read the full study report here.


If you have any further questions regarding the use of Solus or other media formulations with Solus kits then please contact us and we will be happy to help.